Continuous long josephson junction logic gate system

Abstract

One example includes a long Josephson junction gate system that includes a continuous long Josephson junction. The continuous long Josephson junction includes a dielectric layer, an electrode layer formed on the dielectric layer and extending along a soliton propagation direction on the dielectric layer, and a dielectric oxide layer formed on the electrode layer and extending along the soliton propagation direction. The continuous long Josephson junction also includes a metallic signal layer formed on the dielectric oxide layer and extending along the soliton propagation direction entirely over the dielectric oxide layer. The arrangement of the continuous long Josephson junction can be approximated by a repeating sequence of a grounded Josephson junction and an inductor to provide a critical current and inductance that define a soliton energy of a soliton propagating in the continuous long Josephson junction.

What is claimed is: 
     
         1 . A long Josephson junction gate system comprising a continuous long Josephson junction, the continuous long Josephson junction comprising:
 a dielectric layer;   an electrode layer formed on the dielectric layer and extending along a soliton propagation direction on the dielectric layer;   a dielectric oxide layer formed on the electrode layer and extending along the soliton propagation direction; and   a metallic signal layer formed on the dielectric oxide layer and extending along the soliton propagation direction entirely over the dielectric oxide layer, the arrangement of the continuous long Josephson junction being approximated by a repeating sequence of a grounded Josephson junction and an inductor to provide a critical current and inductance that define a soliton energy of a soliton propagating in the continuous long Josephson junction.   
     
     
         2 . The system of  claim 1 , wherein the metallic signal layer has a width of the extension along the soliton propagation direction that is selected to define the critical current and the inductance of the continuous long Josephson junction. 
     
     
         3 . The system of  claim 1 , wherein the metallic signal layer has a length of the extension along the soliton propagation direction of N continuous long Josephson junction portions of approximately equal length in the sequence. 
     
     
         4 . The system of  claim 3 , wherein each of the continuous long Josephson junction portions is approximated as a structure of the grounded Josephson junction and the inductor having a portion critical current and a portion inductance. 
     
     
         5 . The system of  claim 4 , wherein each continuous long Josephson junction portion has a width of the extension along the soliton propagation direction that is selected to define the portion critical current and the portion inductance. 
     
     
         6 . The system of  claim 5 , wherein the portion critical current and the portion inductance is approximately equal to 1/N times the critical current and the inductance of the continuous long Josephson junction. 
     
     
         7 . The system of  claim 3 , wherein the N units corresponding to each continuous long Josephson junction portion is formed as a unitary structure with respect to the electrode layer, the dielectric oxide layer, and the metallic signal layer. 
     
     
         8 . A superconducting circuit comprising the long Josephson junction gate system of  claim 1 . 
     
     
         9 . The superconducting circuit of  claim 8 , further comprising a discrete long Josephson junction comprising:
 circular Josephson junctions formed in the electrode layer, the dielectric oxide layer, and the metallic signal layer;   inductors formed from a metal and coupled between pairs of the circular Josephson junctions based on respective vias that extends to portions of the metallic signal layer that form the circular Josephson junctions.   
     
     
         10 . The circuit of  claim 9 , wherein the continuous long Josephson junction and the discrete long Josephson junction are routed in an orthogonal manner such that the continuous long Josephson junction extends beneath the inductor of the discrete long Josephson junction orthogonally with respect to the discrete long Josephson junction. 
     
     
         11 . A method for forming a long Josephson junction logic gate system comprising forming a continuous long Josephson junction, wherein forming the continuous long Josephson junction comprises:
 forming an electrode layer on a dielectric layer;   forming a dielectric oxide layer on the electrode layer;   forming a metallic signal layer over the dielectric oxide layer; and   etching at least the metallic signal layer to a width along a soliton propagation direction entirely over at least a portion of the dielectric oxide layer to provide an arrangement of the continuous long Josephson junction that is approximated by a repeating sequence of a grounded Josephson junction and an inductor to provide a critical current and an inductance that defines a soliton energy of a soliton propagating in the continuous long Josephson junction based on the width.   
     
     
         12 . The method of  claim 11 , wherein forming the metallic signal layer comprising forming the metallic signal layer at a length of N portions of approximately equal length along the soliton propagation direction. 
     
     
         13 . The method of  claim 12 , wherein each continuous long Josephson junction portion is arranged to approximate the grounded Josephson junction having a defined portion critical current and the inductor having a defined portion inductance. 
     
     
         14 . The method of  claim 13 , wherein etching the metallic signal layer comprises etching the metallic signal layer of each continuous long Josephson junction portion to have a width of the extension along the soliton propagation direction that is selected to provide the defined portion critical current and the defined portion inductance. 
     
     
         15 . The method of  claim 14 , wherein the defined portion critical current and the defined portion inductance is approximately equal to 1/N times the critical current and the inductance, respectively, of the continuous long Josephson junction. 
     
     
         16 . A long Josephson junction gate system comprising a continuous long Josephson junction, the continuous long Josephson junction comprising:
 a dielectric layer;   an electrode layer formed on the dielectric layer and extending along a soliton propagation direction on the dielectric layer;   a dielectric oxide layer formed on the electrode layer and extending along the soliton propagation direction; and   a metallic signal layer formed on the dielectric oxide layer and extending along the soliton propagation direction entirely over the dielectric oxide layer at a length of N continuous long Josephson junction portions of approximately equal length,   wherein each of the continuous long Josephson junction portions is approximated by a structure of a grounded Josephson junction and an inductor to provide a portion critical current and a portion inductance, such that the arrangement of the continuous long Josephson junction has a critical current that is a sum of the portion critical current of each of the N continuous long Josephson junction and an inductance that is a sum of the portion inductance of each of the N continuous long Josephson junction.   
     
     
         17 . The circuit of  claim 16 , wherein each continuous long Josephson junction portion has a width of the extension along the soliton propagation direction that is selected to define the portion critical current and the portion inductance, wherein the portion critical current and the portion inductance is approximately equal to 1/N times the critical current and the inductance of the continuous long Josephson junction. 
     
     
         18 . The circuit of  claim 16 , wherein the metallic signal layer has a width of the extension along the soliton propagation direction that is selected to define the critical current and inductance of the continuous long Josephson junction. 
     
     
         19 . The circuit of  claim 16 , wherein each continuous long Josephson junction portion has a width of the extension along the soliton propagation direction that is selected to define the portion critical current and the portion inductance. 
     
     
         20 . The circuit of  claim 16 , further comprising a discrete long Josephson junction comprising:
 circular Josephson junctions formed in the electrode layer, the dielectric oxide layer, and the metallic signal layer;   inductors formed from a metal and coupled between pairs of the circular Josephson junctions based on respective vias that extends to portions of the metallic signal layer that form the circular Josephson junctions, wherein the continuous long Josephson junction and the discrete long Josephson junction are routed in an orthogonal manner such that the continuous long Josephson junction extends beneath the inductor of the discrete long Josephson junction orthogonally with respect to the discrete long Josephson junction.